package com.atxiaodei.springcloud.lb;

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

@Component
@Slf4j
public class MyLoadBalancer implements LoadBalancer {

    private AtomicInteger atomicInteger=new AtomicInteger(0);

    // 考虑到多线程，返回第几次访问
    private final int getAndIncrement(){
        int current;
        int next;
        do {
            current=this.atomicInteger.get();
            next=current >= 2147483647?0:current+1;

        }while(!atomicInteger.compareAndSet(current, next));
        //第一个参数是期望值，第二个参数是修改值是
        log.info("*******第几次访问，次数next: "+next);
        System.out.println("*******第几次访问，次数next: "+next);
        return next;
    }

    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        int index=getAndIncrement()%serviceInstances.size();
        return serviceInstances.get(index);
    }
}
